1. Field of the Invention
The present invention relates to a digital broadcasting receiving apparatus mounted on a movable body such as a car.
2. Description of the Related Art
Terrestrial digital audio broadcasting can transmit diversified multimedia information using character data and graphics data together with high-quality audio information differently from conventional analog broadcasting transmitting only audio information. Test broadcasts of such terrestrial digital audio broadcasting are scheduled in the Metropolis of Tokyo and the Osaka Prefecture in Japan in the first half of 2003.
As such a technique for broadcasting multimedia information, JP-A-11-317711 discloses a multimedia data broadcast program creating method for drawing a broadcast program for multimedia data to be broadcast on a broadcast channel. According to this multimedia data broadcast program creating method, a database including multimedia objects such as graphic and document files is constructed. Each of the multimedia objects is added with a descriptive text to be used for retrieving the multimedia object from the database. Next, a list of multimedia objects chosen in the database and a broadcast program following each of the multimedia objects and including transmission criteria such as transmission date and hour are extracted from the database. The transmission criteria on which possibility of transmission of the broadcast program is judged include the date and hour set in advance and an event depending on the broadcast program. Each multimedia object is broadcast according to such criteria.
In addition, JP-W-2000-502795 discloses multimedia information equipment for automatically broadcasting a multimedia animation in accordance with the geographic location of a vehicle and the date and hour. This information equipment is constituted by a fixed information station installed in a travel agency and an in-vehicle information station mounted on a vehicle. Each of the two stations has a floppy disk drive for storing information in a floppy disk and reading the stored information therefrom, or a transmission apparatus with a radio transmitter-receiver for transmitting and receiving travel parameters. Further, the in-vehicle information station has a broadcasting travel parameter stock apparatus for storing multimedia animations including information such as itineraries, and a position measuring apparatus having a global positioning system called GPS. The in-vehicle information station broadcasts a multimedia animation recorded in the stock apparatus in accordance with the travel parameters including the location of the vehicle and the date and hour and stored in a floppy disk or transmitted from the fixed information station, and the geographic data of the current location of the vehicle from the position measuring apparatus.
Terrestrial digital broadcast can be received not only by receivers fixed indoors but also by receivers mounted on moving bodies such as cars. Accordingly, a receiver which can watch and listen to a part of information at any desired place is demanded.
JP-A-7-15360 discloses electronic equipment with a built-in radio and an antitheft device, which can listen to radio broadcast by its operating unit itself. The electronic equipment has an operating unit removably attached to a body fixedly mounted on a car. This operating unit has a tuner for receiving radio waves from an antenna, a PLL built-in microcomputer for making control to tune in on a desired station from the received radio waves of the tuner, and a battery for supplying power to the tuner and the microcomputer when the operating unit is removed from the body. When the operating unit is removed from the body, an audio signal included in a radio wave received by the tuner is fed to headphones connected to the operating unit through an amplifier provided in the operating unit. Thus, the operating unit can be used as a headphone radio.
An in-vehicle digital broadcasting receiving apparatus mounted on a car is fixed to the interior of the car so that multimedia information such as character data included in digital broadcasting cannot be browsed outside the car. On the other hand, when the in-vehicle digital broadcasting receiving apparatus itself is designed to be removably mounted on a car, the apparatus itself is too large to be carried easily.